When carrying out certain medical procedures, for example, radiation therapy or orthopedic settings, thermoplastic materials are frequently used on a patient for fixation (i.e., casting) purposes. In general, thermoplastic materials, when warmed to a temperature within a threshold range, become easily pliable, and, when cooled below that threshold range, become relatively rigid. To this end, thermoplastic materials are often warmed and molded into a shape which complements a body part on a patient, so as to help the patient maintain that particular body part in a required fixed position for an extended period of time or to replicate that exact position over the course of multiple treatments. For example, in radiation therapy involving the head area, a patient may find it difficult to maintain his or her head in a certain position for the entire treatment or to replicate the same fixed position between treatments. As such, a thermoplastic material may be warmed and molded into a cast corresponding to the shape of the patient's head for maintaining the patient's head in the required position. The thermoplastic material may also be used for orthopedic purposes. For example, by setting a cast of thermoplastic material about an arm or leg having a bone fracture, movement of the arm or leg may be minimized to aid in the healing of the fracture.
Currently, to transform the thermoplastic material from a relatively rigid to a more pliable state, the thermoplastic material is heated in a warming chamber by a conductive heat-source. An example of such a warming chamber is disclosed in U.S. Pat. No. 5,816,797.
The thermoplastic material may alternatively be soaked in a hot water bath to provide uniform heating. However, a water bath is generally bulky and large in size and, therefore, may take up much of the needed space in a limited work area. Moreover, the bath may need to be both refilled and cleaned regularly due to issues associated with evaporation and bacterial growth. The cleaning presents spillage hazard for people and instruments in the vicinity of the water bath.
Accordingly, it is desirable that a cast for fixation purposes be formed from a thermoplastic material that has been warmed to a pliable state more quickly and reliably than existing warming chambers.